X-ray and EUV Observations of GOES C8 Solar Flare Events

TL;DR

This study analyzes C8 class solar flares using X-ray and EUV data, revealing correlations between flare phases, energy partitioning, and thermal parameters, and demonstrating that longer flares are cooler and larger, while shorter ones are hotter and smaller.

Contribution

It provides new insights into the thermal and energetic properties of C8 class solar flares, linking observational data with flare models and scaling laws.

Findings

Decay duration proportional to rise duration

Radiated energy during rise phase correlates with total energy

Longer flares are cooler with larger volumes

Abstract

We present an analysis of soft X-ray (SXR) and extreme-ultraviolet (EUV) observations of solar flares with an approximate C8 GOES class. Our constraint on peak GOES SXR flux allows for the investigation of correlations between various flare parameters. We show that the the duration of the decay phase of a flare is proportional to the duration of its rise phase. Additionally, we show significant correlations between the radiation emitted in the flare rise and decay phases. These results suggest that the total radiated energy of a given flare is proportional to the energy radiated during the rise phase alone. This partitioning of radiated energy between the rise and decay phases is observed in both SXR and EUV wavelengths. Though observations from the EVE show significant variation in the behavior of individual EUV spectral lines during different C8 events, this work suggests that broadband EUV emission is well constrained. Furthermore, GOES and AIA data, allow us to determine several thermal parameters (e.g. temperature, volume, density, and emission measure) for the flares within our sample. Analysis of these parameters demonstrate that, within this constrained GOES class, the longer duration solar flares are cooler events with larger volumes capable of emitting vast amounts of radiation. The shortest C8 flares are typically the hottest events, smaller in physical size, and have lower associated total energies. These relationships are directly comparable with several scaling laws and flare loop models.